Interleukin 12 (IL-12) is a heterodimeric, pro-inflammatory cytokine with varied functions in the immune system. For example, IL-12 enhances cytolytic activity by inducing the production of effector cytokines, e.g., interferon-γ (IFN-γ), TNF-α, and/or granulocyte macrophage colony stimulating factor (GM-CSF). IL-12 also enhances the production of T helper 1 (Th1) immunoglobulins by B cells and induces the differentiation of (Th1) cells.
Although recombinant IL-12 has demonstrated potent anti-cancer activity in animal models, recombinant IL-12 has provided only limited results in clinical trials (Del Vecchio et al. Clin. Cancer Res. 13(16):4677-85 (2007)). In addition, systemic administration of IL-12 in a phase II clinical trial for renal cell carcinoma resulted in severe toxicity for most of the enrolled patients and the deaths of two patients (Cohen, J. Science 270:(5238)908 (1995)).
In spite of considerable research into cancer treatments, there is a need for improved compositions and methods for treating and/or preventing cancer.